2015-09-15 06:12:46 +01:00

61 lines
1.8 KiB
JavaScript

import pull from "lodash/array/pull";
export default function ({ types: t }) {
function isProtoKey(node) {
return t.isLiteral(t.toComputedKey(node, node.key), { value: "__proto__" });
}
function isProtoAssignmentExpression(node) {
var left = node.left;
return t.isMemberExpression(left) && t.isLiteral(t.toComputedKey(left, left.property), { value: "__proto__" });
}
function buildDefaultsCallExpression(expr, ref, file) {
return t.expressionStatement(t.callExpression(file.addHelper("defaults"), [ref, expr.right]));
}
return {
visitor: {
AssignmentExpression(path, file) {
if (!isProtoAssignmentExpression(path.node)) return;
var nodes = [];
var left = path.node.left.object;
var temp = path.scope.maybeGenerateMemoised(left);
if (temp) nodes.push(t.expressionStatement(t.assignmentExpression("=", temp, left)));
nodes.push(buildDefaultsCallExpression(path.node, temp || left, file));
if (temp) nodes.push(temp);
return nodes;
},
ExpressionStatement({ node }, file) {
var expr = node.expression;
if (!t.isAssignmentExpression(expr, { operator: "=" })) return;
if (isProtoAssignmentExpression(expr)) {
return buildDefaultsCallExpression(expr, expr.left.object, file);
}
},
ObjectExpression({ node }, file) {
var proto;
for (var prop of (node.properties: Array)) {
if (isProtoKey(prop)) {
proto = prop.value;
pull(node.properties, prop);
}
}
if (proto) {
var args = [t.objectExpression([]), proto];
if (node.properties.length) args.push(node);
return t.callExpression(file.addHelper("extends"), args);
}
}
}
};
}